Expanding knowledge of developmental mechanisms beyond traditional model organisms should provide insights into the function of basic biological processes, and how these processes are employed in different environments. The beetle Tribolium is emerging as an important alternative to Drosophila. The focus of this proposal will be on the establishment of the dorsal ventral (DV) axis in Tribolium. The importance of oocyte cytoskeletal organization and function will be examined using antibody staining, transgenic fusion proteins and drug treatments. Then, expression and function of genes involved in sending and receiving signals from the oocyte nucleus will be examined by gene expression patterns and RNA interference. Candidate genes will be identified by homology to participants in the Drosophila DV system, and by sequencing and testing ESTs from Tribolium ovaries. At later stages, microarrays will be used to identify targets of the Tribolium Dorsal protein gradient. Potential targets will be identified as those whose expression levels change significantly when Dorsal function is manipulated. Finally, initial steps to further broaden understanding of DV patterning will be taken using three additional insects species amenable to manipulation in the lab.